[GreenKeys] Fwd: Looking for an IBM 2741 or similar

[Cory Heisterkamp]

Jim Haynes was kind enough to hook me up with an I/O Selectric a couple
years back and the rather interesting limitation is that they really prefer
to receive text at a fixed cadence. Apparently, having to overcome the loss
of inertia from letting the type ball and mechanism settle out between
strikes adds enough wear to the moving parts that cycle switches are
included to provide feedback to the electronics so that the next tilt and
rotate code can be sent during the most opportune time. I think this is
also mentioned in one of the interface documents.

This particular unit looks like it was used as part of a SINS submarine
navigation system, but unfortunately a couple of code setup coils are open
and it's a rather...delicate...mechanism to dig into : )

-Cory

On Wed, Aug 10, 2016 at 4:05 PM, Ed Sharpe Archivist for SMECC via
GreenKeys <greenkeys at mailman.qth.net> wrote:

> switching type balls from different coded machines was always a great
> prank to play on some unsuspecting  target <grin!>  Ed#
>
>
>
>
>
> In a message dated 8/10/2016 1:53:25 P.M. US Mountain Standard Time,
> douglas-w-jones at uiowa.edu writes:
>
> On Aug 10, 2016, at 11:22 AM, Richard wrote:
>
> > Just to be clear: An IBM 2741 is not a teletype; it's a Selectric
> > typewriter mechanism with IO circuitry running at 34.5 baud.
>
> And yet, somehow able to achieve 15 characters per second with 8-bit
> EBCDIC data communications.  I used them quite a bit for a while, and
> remember the solid chunking clatter of their typing, quite different from
> the sound of a Teletype.  Also, you could change the typeball in order to
> completely baffle the next person to use it.
>
>         Doug Jones
>         jones at cs.uiowa.edu
>
>
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
> 2002-to-present greenkeys archive: http://mailman.qth.net/
> pipermail/greenkeys/
> 1998-to-2001 greenkeys archive: http://mailman.qth.net/
> archive/greenkeys/greenkeys.html
> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
> http://comcents.com/tty/greenkeyssearch.html
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to coryheisterkamp at gmail.com
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20160810/ad6197c4/attachment.html>